1. Field of the Invention
The present invention relates to a leisure shoe or sandal. More particularly, the invention relates to a leisure shoe in which the top of the sole (usually a laminate) comprised of a synthetic polymer is easily bonded to the bottom of a synthetic polymeric shoe upper-insole comprising a second different synthetic polymer. The bonding between the different polymers using adhesives is improved using a fabric or perforated interlayer between the shoe upper-insole and the composite sole. As a result, the manufacturing process is simplified, and the shoe upper-insole and sole comprising different polymeric materials of the composite leisure shoe do not separate with extensive wear.
A leisure shoe sole made of synthetic polymers does not bond well to a synthetic polymeric shoe upper-insole, and the polymers are often inferior to natural materials. Further, the use of certain adhesives for bonding synthetic polymeric materials to each other is not completely satisfactory. Thus, peeling (or separation) of the different synthetic resins or polymers usually occurs quickly at stress points between the upper-insole and the sole during normal use. These stress points occur in the heel, toe, instep and sole portions of the shoe in normal walking. Further, for many people the ankle also turns out during walking which produces additional stress points on the sole. All of these motions create shear or peeling motions where different polymers of the sole are joined by adhesive. These stress points cause the polymers to separate. The different polymeric parts of the leisure shoe may be reinforced by nailing, stapling or sewing, because the soles also separate in time. Further, the nails or staples can become dangerous when sole wear is excessive. But these reinforcing methods are usually not desirable as far as the wearer of the shoe is concerned.
2. Related Art
The sole of a leisure shoe or sandal for beach or casual everyday wear is commonly made of different synthetic resins such as polyvinylchloride (P.V.C.), ethylene vinyl acetate copolymer resin (E.V.A.), polyamide resins, polyurethane resins, polycarbonate resins, and the like. The earlier-used natural materials, such as leather, cloth, or rubber, often do not have the necessary wearing or esthetic qualities, and are usually more costly as well.
In many instances, the bonding of a leather or artifical leather sole to a synthetic polymer shoe upper using an adhesive is not completely satisfactory.
Some patent references of interest in the shoe art include the following:
______________________________________ Re: Number Patentee Date ______________________________________ 15,794 Cary 1924 1,316,562 Dunphy 1919 2,323,562 Nugent 1943 2,350,852 Wehr 1944 2,619,441 Levy 1952 3,170,252 Ravich 1965 3,174,236 Field 1965 3,234,668 Radcliffe 1966 3,257,743 Closson, Jr. et al. 1966 3,345,664 Ludwig 1967 3,590,411 Zemlin 1971 3,602,931 MacArthur et al. 1971 3,629,050 Weinstein et al. 1971 3,693,269 Guarrera 1972 3,711,969 Weinstein et al. 1973 3,812,604 Sato 1974 4,245,406 Landay et al. 1981 4,331,731 Seike et al 1982 4,335,528 Watanabe 1982 4,434,518 Watanabe 1984 ______________________________________
However, none of these patents describe the composite leisure shoe of the present invention or the method of manufacturing it.
It is desirable to have a composite leisure shoe and a method of manufacturing it in which the bonding of the different synthetic polymers does not separate during normal use.